Orbiter gets fresh 3-D look at Phobos

The European Space Agency's Mars Express probe captured this stereo view of the Martian moon Phobos on Jan. 9. Some areas of the image have been adjusted to fix distortions or gaps for 3-D viewing using red-blue glasses.

Phobos, the bigger of Mars' two moons, is getting repeated once-overs by Mars Express' high-resolution camera in part because a good atlas is so important for the Russian-led Phobos-Grunt mission, now due for launch in November. The Russians plan to put a lander down on the ground ("Grunt" is Russian for "ground"), and the Mars Express imagery is helping refine their mission trajectory. Phobos-Grunt's lander is to collect rock and dust samples from the surface and send them back to Earth in a capsule.

"With every Phobos image from the stereo camera, we can improve the three-dimensional model of the Martian moon," Jürgen Oberst of the German Aerospace Center's Institute of Planetary Research said Friday in an image advisory.

G. Neukum / FU Berlin / DLR / ESA

The ellipses on this image of Phobos show the previously planned landing area for the Phobos-Grunt mission in red, and the currently planned landing area in blue.

These pictures were taken on Jan. 9 during Mars Express' last scheduled encounter with the 12-by-14-by-17-mile moon. The flyby brought the orbiter within an altitude of 62 miles (100 kilometers) — so close that the camera had to turn at its maximum rate as it passed over Phobos.

Phobos' characteristic grooves show up clearly in these photos — but it's not yet clear exactly what caused them. One hypothesis is that they're splat marks from debris that was kicked up by impacts on Mars. The Planetary Society's Emily Lakdawalla explains the concept in this posting from an earlier Phobos flyby.